1. Field of the Invention
The present invention relates to a respiratory system and more particularly, is concerned with providing fresh, breathable air from contaminated air for use in aircraft and providing visibilty to escaping aircraft passengers involved in an aircraft fire as well as other vehicle use and non-vehicle use. When installed in an aircraft the present invention embodies the function of the present supplemental oxygen mask, common in the art and referred to as the "gold cup", providing supplemental oxygen in cases of aircraft decompression.
2. Description of the Prior Art
In the past, many smoke hoods have been designed to protect the wearer by providing fresh breathable air from air in environments contaminated by smoke and noxious gases.
The patent to Levine, U.S. Pat. No. 4,559,939 discloses a supplemental air tank and hood system. The patent to Birch, U.S. Pat. No. 4,116,237 discloses a supplemental air tank and hood system. These devices only provide dry filters that mainly remove particulates.
The Wong invention, U.S. Pat. No. 4,554,683 provides a barrel shaped smoke hood to provide the wearer with a volume of breathable air within the hood sufficient to sustain the wearer for a short period of time. This hood works in situations involving high rise building fires where fresh, breathable air is available for a period of time prior to contamination by smoke and noxious gases. The major drawback of this hood when used in the aircraft fire situation, is the consumption of the fresh, breathable air and generation of carbon dioxide within the hood, leading to hypercapnia and anoxia. In the aircraft fire situation, the time from onset of fire to time of evacuation may exceed the capacity of the Wong invention.
The instant invention provides an oral-nasal mask which may be connected to any air supply and may be connected to an aircraft's emergency air supply and an air purification system through a wet chemical filter such that fresh, breathable air is available to the passenger at any point during the fire thereby eliminating the need to "fill" the hood with fresh air prior to donning the hood. The oral-nasal mask provides breathable air prior to placement of the hood over the head of the user and after placing the hood over the user's head.
While the Wong invention does mention that optional filters may be attached to the barrel shaped hood, the hood may not provide the passenger with fresh, breathable air prior to the passenger's asphyxiation or suffication due to the smoke and noxious fumes even with the incorporation of the optional filters. Because the hood allows atmospheric air, which is likely to be contaminated in the aircraft fire case, into the hood prior to incorporation on the wearer, the wearer will have to take several breaths of contaminated air before any filtering system allows the purified air to enter the barrel shaped hood. Survivors of recent aircraft fires have stated that one and two breaths of the smoke and noxious gases present in the aircraft fire resulted in the passenger's lungs feeling solidified and in the passenger's experiencing extreme sleepiness. The passengers of aircraft fires cannot risk taking several breaths of the contaminated, toxic, atmospheric air within the Wong hood prior to receiving the purified air where such immediate and critical symptoms occur from one or two breaths.
The instant invention provides a compact oral-nasal mask and hood. The invention incorporating the oral-nasal mask does not require a user or passenger to take several breaths of the contaminated, surrounding atmospheric air prior to receiving the fresh, breathable air. The oral-nasal mask is of relatively small volume, just sufficient to cover the user's or passenger's mouth and nose region such that the passenger will receive fresh, breathable air immediately upon the user's or passenger's first breath from a supply or from the aircraft supply and/or from the surrounding air filtered through the wet and dry purification filter.
Further, traditional filters are not effective in removing some toxic materials, specifically Hydrogen Cyanide, Hydrogen Chloride, Hydrogen Floride, and Carbon Monoxide, some of the more lethal and commonly occurring gases in modern building fires or in airplane fires. The disclosed chemical filter system employing both a wet and dry chemical cleansing system within the instant invention is more effective in reducing levels of Hydrogen Cyanide, Carbon Monoxide and other gases which enter the filtration system. The wet filter scrubs the incoming contaminated air in a wet bath of bases to neutralize the acidic toxic gases. A porous plastic material is used that allows the liquid to remain inside the purifier but allows the user's lungs to draw the contaminated air through the interior of the porous plastic section. The porous plastic material is a hydrophobic material composed of polyethylene or other common plastics, a tradename common in this application is POREX POROUS POLYETHYLENE.
Smoke hoods that have been proposed are disclosed in several prior patents including: U.S. Pat. Nos. 4,554,683, 4,231,118, 3,562,813, and 3,458,864. However, the novelty of the instant invention is the relatively small compact respiratory system for use in a building or vehicle or an aircraft and in leaving same. The respiratory system also includes a wet chemical scrubbing filter for cleaning a room or cabin air of toxic and other gases connected to the oral-nasal mask, the combination of a collapsible hood that is connected to the oral-nasal mask allowing the oral-nasal mask to be placed over the user's nose and mouth prior to covering the user's eyes with hood. While the above mentioned inventions utilize the protective hood to surround the user with breathable air, the protective hood in the instant invention has as one of its primary purpose, not to surround the user with fresh air, as the oral-nasal mask already provides this, but to insulate the user's eyes from the irritating effects of the noxious gases and soot disposition by filling the hood with the user's exhaust gases from the oral-nasal mask. In addition, the present invention provides the passenger with fresh, breathable air before the user or passenger dons the smoke hood. This psychological advancement provides the passengers with the security of fresh breathable air before surrounding their heads with the air impervious hood.
In addition, no other prior art incorporates a dual air supply system providing the user or passenger with either, or both, fresh air from the local supply aircraft's emergency air source if provided or from the contaminated surroundings by filtering same through a wet chemical filter. The instant invention may rely entirely upon the ambient air supply to provide the user or passenger with fresh, breathable air from contaminated surrounding air for a temporary period sufficient to escape from the room, the surrounding area or the cabin of an aircraft. The filtering system is stored in the cup-like oral-nasal mask. The hood that may be easily placed over the user or passenger is conveniently attached to the outside of the oral-nasal mask.
Consequently, a need exists for an aircraft respiratory system incorporating both an oral-nasal mask providing the passenger with fresh, breathable air from alternative sources, the aircraft's emergency air source and an air purifier source that removes contaminants from the surrounding cabin air, and a protective hood to insulate the passenger from the smoke and noxious gases associated with an aircraft fire to improve passenger's visibility by filling the hood with the user's exhausted gas during an escape from the aircraft. The same compact respiratory system may be used in other vehicles or by firemen or the like. The wet chemical air purifier continues to work after the user detaches himself from the bottled air or the aircraft's emergency air in order to exit the area, room or aircraft.